Activation of plasmacytoid dendritic cells in neuromyelitis optica patients (P5.268)

OBJECTIVE: To investigate the role of PDCs in the peripheral blood of NMO patients. BACKGROUND: Neuromyelitis optica (NMO) is an autoimmune astrocitopathy mediated by antibodies against the water channel aquaporin 4 (AQP4). NMO lesions occur predominantly in the spinal cord and optic nerves, and attacks are often debilitating. Production of antibodies is dependent on various and complex mechanisms. Plasmacytoid dendritic cells (PDCs) are known for their ability to secrete Interferon alpha (IFN-α) and this cytokine contributes to the production of autoantibodies. DESIGN/METHODS: PDCs from the peripheral blood of twelve NMO patients were isolated using magnetic beads and the expression of IDO e IFN alpha was determined by real time PCR. RESULTS: We demonstrated that although all the patients enrolled were under immunosuppressive treatment pDCs from peripheral blood were activated and showed an increased expression of IFN-α, as well as low expression of indoleamine 2,3 dioxinagese (IDO). CONCLUSIONS: Since IDO is involved in the activation of regulatory T cells, and IFN- α activates the synthesis of autoantibodies, these results suggest that PDCs might play a role in stimulating antibody production in NMO patients even while under immunosuppressive treatment, through IFN-α secretion. Study Supported by: FAPESP, CAPES and CNPq Disclosure: Dr. Dias-Carneiro has nothing to disclose. Dr. Andrade has nothing to disclose. Dr. Von Glehn Silva has nothing to disclose. Dr. Dionete has nothing to disclose. Dr. Moraes has nothing to disclose. Dr. Brandao has nothing to disclose. Dr. Boldrini has nothing to disclose. Dr. Damasceno has nothing to disclose. Dr. Pradella has nothing to disclose. Dr. Morais has nothing to disclose. Dr. Russini has nothing to disclose. Dr. Farias has nothing to disclose. Dr. Damasceno has nothing to disclose. Dr. Tilbery has nothing to disclose. Dr. Santos has nothing to disclose.